This invention relates to an electrical park latch actuator for the automatic transmission selector lever of a road vehicle.
It is usual for the selector lever of a vehicle automatic transmission system to incorporate a manually operable release button or the like which must be operated by the vehicle driver in order to release a latch mechanism permitting the selector lever to be moved between certain operating positions. For example, it is usual for the lever to be latched in the "Park" position so that the release button must be operated to permit the lever to be moved from the park position.
For safety reasons it is usual for there to be a requirement that both the ignition switch of the vehicle is in the "on" position and the brake pedal of the vehicle is depressed before the release button can be operated to release the latch mechanism freeing the selector lever for movement from the park position.
Conventionally, as illustrated in, for example, U.S. Pat. No. 5,489,246, the ability to operate the release button, to free the selector level for movement from its park position, is controlled by a first solenoid responsive to energization of the ignition circuits of the vehicle, and a second solenoid responsive to the position of the brake pedal of the vehicle. The first and second solenoids include plungers which cooperate independently of one another with respective cam/abutment regions of a pushrod moving with the release button.
It is an object of the present invention to provide an electric park latch actuator which can be responsive to the energization of the ignition circuit of the vehicle and the depression of the brake pedal of the vehicle in a simple and convenient form.